JP2949427B2 - Joint treatment method for composite floor slab - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a synthetic slab,
Specifically, the present invention relates to a joint processing method for floor slabs.

[0002]

2. Description of the Related Art A construction method using a composite floor slab has been proposed as one of floor construction methods. The composite slab is obtained by arranging a plurality of PC (precast concrete) slabs and then casting the upper concrete on the slab, which has an advantage that the operation is simple. When constructing such a composite slab, the joint between the PC slabs is usually processed by embedding a backup material such as a foamed resin material. Specifically, as shown in the cross-sectional view of FIG. 3, when a step 102 is provided at an end of the PC floor slab 101 and the PC floor slab 101 abuts, a recess 103 is formed.
After the backup material 104 is inserted into the gap and the gap is sealed, an upper concrete 105 is poured on the upper surface of the floor slab 101.

[0003] On the other hand, the upper concrete of the composite floor slab has a problem that cracks are easily generated at the joints. This is because concrete shrinks at the joint due to a difference in cross-sectional area between the joint and the peripheral part and compatibility with the PC slab. In order to solve this, measures such as adopting concrete and curing method with less shrinkage or increasing the amount of reinforcement in concrete have been taken, but cracks in joints still occur There has been a demand for a method for reducing the number of particles.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a joint slab jointing method for reducing cracks in upper concrete at joints.

[0005]

According to the present invention, there is provided a step of laying a PC slab having a shelf having an upper surface at an abutting end lower than an upper surface at a center portion, and a gap between the PC slabs. Sealing the mortar or concrete between the PC slabs and filling the recesses formed by the respective shelves with the mortar or concrete. And a step of casting concrete.

In this means, a PC slab having a shelf at the abutting end is used, and mortar or concrete is filled in a recess formed by the shelf of an adjacent PC slab, ie, a joint portion. When this mortar or concrete hardens, it causes cracks at the boundary with the PC slab, that is, at both ends of the recess, due to differences in shrinkage and the like,
After this, the upper concrete is cast. As a result, the cause of the cracks in the upper concrete is replaced by the cracks at both ends of the concave portion from the joints at the beginning. Therefore, the shrinkage of the concrete is not concentrated in one place as in the prior art, but is dispersed at least at both ends of the concave portion, so that the unevenness of the shrinkage is reduced. Only occurs. Therefore, the joint treatment method of the present invention has an effect that cracks in the upper concrete can be reduced to a minimum.

In the present invention, the term "butting end" means an end on the side where the adjacent PC floor slabs face each other at the time of placement, and the upper surface means the side on the side which comes into contact with the upper concrete to be cast later. Means the surface of PC slab. The shelf preferably has a depth from the upper surface of the central portion of about half the thickness of the PC slab, and a width from the end surface on the butt side of about 3 times the depth. It may be formed so as to be inclined or stepwise. The gap between the PC slabs is provided as a clearance for placing the PC slabs against each other, and is usually about 10 to 20 mm.

The seal is to be applied to the gap in order to prevent the mortar or concrete from leaking from the gap between the PC slabs at the joints. The sealing material to be used is a gum tape or the like. A simple one is enough. The step of placing the upper concrete on the upper surface of the PC slab also involves the necessary operations such as reinforcing arrangement and piping.

[0009]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 illustrates an aspect of a joint in each step of the joint treatment method according to the present invention. First, a plurality of P
The C slab is placed (FIG. 1 (a)). Each PC slab is
As shown in the perspective view of FIG. 2, at the both ends which are to be brought into contact with another adjacent PC slab when being arranged,
It has a shelf 1a formed so that the upper surface is positioned lower than the central upper surface 1b.

Next, in order to close the gap 2 between the PC floor slabs, the adhesive tape 3 is stretched from the shelf 1a to the adjacent shelf 1a.
Is adhered (FIG. 1 (b)), and the mortar 4 is filled in the recess 5 formed by the adjacent shelf 1a (FIG. 1).
(C)). The reason why the gum tape 3 is applied is to prevent the mortar 4 from leaking from the gap 2. Thereafter, the mortar 4 is left for several days until it is hardened.

When the mortar 4 is hardened, cracks 7 are generated in the vicinity of the edge 6 of the concave portion 5 due to a difference in shrinkage from the PC slab 1 (FIG. 1D). After confirming the cracks 7, necessary work such as reinforcing bars 8a and piping is performed on the PC slab 1, and then the upper concrete 8 is cast, and the work is completed (FIG. 1 (e)).

[Brief description of the drawings]

FIG. 1A is a view showing a process in which PC floor slabs 1 are arranged in abutting relation. FIG. 4B is a diagram illustrating a process of attaching a gum tape 3 to close the gap 2. (C) It is a figure showing the process which filled the mortar 4. (D) It is a figure which shows the aspect which the mortar 4 hardened. (E) It is a figure showing the process of casting the upper concrete 8 on PC floor slab 1.

FIG. 2 is an external view of a PC floor slab.

FIG. 3 is a cross-sectional view showing a conventional joint processing method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 PC floor slab 1a Shelf part 2 Gap 3 Gum tape 4 Mortar 5 Depression 6 Edge 7 Crack 8 Upper concrete 101 PC floor slab 102 Step 103 Depression 104 Backup material 105 Upper concrete 106 Rebar

Claims (1)

(57) [Claims] 1. A step of laying a PC slab having a shelf with an upper surface of a butted end lower than an upper surface of a center portion, a step of sealing a gap between the PC slabs,
A step of filling the mortar or concrete in the recess formed by each of the shelves between the C slabs, and after the occurrence of cracks in the mortar or concrete due to hardening,
A step of casting upper concrete on the upper surface of the PC slab.